[DWARF] Make llvm-dwarfdump display location lists in a .dwp file correctly. Fixes PR38990.

Considers the index when extracting location lists from a .dwp file.
Majority of the patch by David Blaikie.

Reviewers: dblaikie

Differential revision: https://reviews.llvm.org/D53155

llvm-svn: 344807

3 files changed, 42 insertions, 30 deletions

diff --git a/llvm/lib/DebugInfo/DWARF/DWARFDie.cpp b/llvm/lib/DebugInfo/DWARF/DWARFDie.cpp
index cf10c1134a7..6b69b822aad 100644
--- a/llvm/lib/DebugInfo/DWARF/DWARFDie.cpp
+++ b/llvm/lib/DebugInfo/DWARF/DWARFDie.cpp
@@ -101,12 +101,10 @@ static void dumpLocation(raw_ostream &OS, DWARFFormValue &FormValue,
 
   FormValue.dump(OS, DumpOpts);
   if (FormValue.isFormClass(DWARFFormValue::FC_SectionOffset)) {
-    const DWARFSection &LocSection = Obj.getLocSection();
-    const DWARFSection &LocDWOSection = Obj.getLocDWOSection();
     uint32_t Offset = *FormValue.getAsSectionOffset();
-    if (!LocSection.Data.empty()) {
+    if (!U->isDWOUnit()) {
       DWARFDebugLoc DebugLoc;
-      DWARFDataExtractor Data(Obj, LocSection, Ctx.isLittleEndian(),
+      DWARFDataExtractor Data(Obj, *U->getLocSection(), Ctx.isLittleEndian(),
                               Obj.getAddressSize());
       auto LL = DebugLoc.parseOneLocationList(Data, &Offset);
       if (LL) {
@@ -117,8 +115,8 @@ static void dumpLocation(raw_ostream &OS, DWARFFormValue &FormValue,
                  Indent);
       } else
         OS << "error extracting location list.";
-    } else if (!LocDWOSection.Data.empty()) {
-      DataExtractor Data(LocDWOSection.Data, Ctx.isLittleEndian(), 0);
+    } else {
+      DataExtractor Data(U->getLocSectionData(), Ctx.isLittleEndian(), 0);
       auto LL = DWARFDebugLocDWO::parseOneLocationList(Data, &Offset);
       if (LL)
         LL->dump(OS, Ctx.isLittleEndian(), Obj.getAddressSize(), MRI, Indent);
diff --git a/llvm/lib/DebugInfo/DWARF/DWARFUnit.cpp b/llvm/lib/DebugInfo/DWARF/DWARFUnit.cpp
index 6c3c62d86ef..dbac5a82b57 100644
--- a/llvm/lib/DebugInfo/DWARF/DWARFUnit.cpp
+++ b/llvm/lib/DebugInfo/DWARF/DWARFUnit.cpp
@@ -39,9 +39,10 @@ void DWARFUnitVector::addUnitsForSection(DWARFContext &C,
                                          DWARFSectionKind SectionKind) {
   const DWARFObject &D = C.getDWARFObj();
   addUnitsImpl(C, D, Section, C.getDebugAbbrev(), &D.getRangeSection(),
-               D.getStringSection(), D.getStringOffsetSection(),
-               &D.getAddrSection(), D.getLineSection(), D.isLittleEndian(),
-               false, false, SectionKind);
+               &D.getLocSection(), D.getStringSection(),
+               D.getStringOffsetSection(), &D.getAddrSection(),
+               D.getLineSection(), D.isLittleEndian(), false, false,
+               SectionKind);
 }
 
 void DWARFUnitVector::addUnitsForDWOSection(DWARFContext &C,
@@ -50,16 +51,18 @@ void DWARFUnitVector::addUnitsForDWOSection(DWARFContext &C,
                                             bool Lazy) {
   const DWARFObject &D = C.getDWARFObj();
   addUnitsImpl(C, D, DWOSection, C.getDebugAbbrevDWO(), &D.getRangeDWOSection(),
-               D.getStringDWOSection(), D.getStringOffsetDWOSection(),
-               &D.getAddrSection(), D.getLineDWOSection(), C.isLittleEndian(),
-               true, Lazy, SectionKind);
+               &D.getLocDWOSection(), D.getStringDWOSection(),
+               D.getStringOffsetDWOSection(), &D.getAddrSection(),
+               D.getLineDWOSection(), C.isLittleEndian(), true, Lazy,
+               SectionKind);
 }
 
 void DWARFUnitVector::addUnitsImpl(
     DWARFContext &Context, const DWARFObject &Obj, const DWARFSection &Section,
-    const DWARFDebugAbbrev *DA, const DWARFSection *RS, StringRef SS,
-    const DWARFSection &SOS, const DWARFSection *AOS, const DWARFSection &LS,
-    bool LE, bool IsDWO, bool Lazy, DWARFSectionKind SectionKind) {
+    const DWARFDebugAbbrev *DA, const DWARFSection *RS,
+    const DWARFSection *LocSection, StringRef SS, const DWARFSection &SOS,
+    const DWARFSection *AOS, const DWARFSection &LS, bool LE, bool IsDWO,
+    bool Lazy, DWARFSectionKind SectionKind) {
   DWARFDataExtractor Data(Obj, Section, LE, 0);
   // Lazy initialization of Parser, now that we have all section info.
   if (!Parser) {
@@ -79,12 +82,12 @@ void DWARFUnitVector::addUnitsImpl(
       std::unique_ptr<DWARFUnit> U;
       if (Header.isTypeUnit())
         U = llvm::make_unique<DWARFTypeUnit>(Context, InfoSection, Header, DA,
-                                             RS, SS, SOS, AOS, LS, LE, IsDWO,
-                                             *this);
+                                             RS, LocSection, SS, SOS, AOS, LS,
+                                             LE, IsDWO, *this);
       else
         U = llvm::make_unique<DWARFCompileUnit>(Context, InfoSection, Header,
-                                                DA, RS, SS, SOS, AOS, LS, LE,
-                                                IsDWO, *this);
+                                                DA, RS, LocSection, SS, SOS,
+                                                AOS, LS, LE, IsDWO, *this);
       return U;
     };
   }
@@ -164,16 +167,25 @@ DWARFUnitVector::getUnitForIndexEntry(const DWARFUnitIndex::Entry &E) {
 }
 
 DWARFUnit::DWARFUnit(DWARFContext &DC, const DWARFSection &Section,
-                     const DWARFUnitHeader &Header,
-                     const DWARFDebugAbbrev *DA, const DWARFSection *RS,
+                     const DWARFUnitHeader &Header, const DWARFDebugAbbrev *DA,
+                     const DWARFSection *RS, const DWARFSection *LocSection,
                      StringRef SS, const DWARFSection &SOS,
                      const DWARFSection *AOS, const DWARFSection &LS, bool LE,
                      bool IsDWO, const DWARFUnitVector &UnitVector)
     : Context(DC), InfoSection(Section), Header(Header), Abbrev(DA),
-      RangeSection(RS), LineSection(LS), StringSection(SS),
-      StringOffsetSection(SOS),  AddrOffsetSection(AOS), isLittleEndian(LE),
-      isDWO(IsDWO), UnitVector(UnitVector) {
+      RangeSection(RS), LocSection(LocSection), LineSection(LS),
+      StringSection(SS), StringOffsetSection(SOS), AddrOffsetSection(AOS),
+      isLittleEndian(LE), isDWO(IsDWO), UnitVector(UnitVector) {
   clear();
+  // For split DWARF we only need to keep track of the location list section's
+  // data (no relocations), and if we are reading a package file, we need to
+  // adjust the location list data based on the index entries.
+  if (IsDWO) {
+    LocSectionData = LocSection->Data;
+    if (auto *IndexEntry = Header.getIndexEntry())
+      if (const auto *C = IndexEntry->getOffset(DW_SECT_LOC))
+        LocSectionData = LocSectionData.substr(C->Offset, C->Length);
+  }
 }
 
 DWARFUnit::~DWARFUnit() = default;
diff --git a/llvm/lib/DebugInfo/DWARF/DWARFVerifier.cpp b/llvm/lib/DebugInfo/DWARF/DWARFVerifier.cpp
index e78e13bf4af..d30600accd0 100644
--- a/llvm/lib/DebugInfo/DWARF/DWARFVerifier.cpp
+++ b/llvm/lib/DebugInfo/DWARF/DWARFVerifier.cpp
@@ -325,9 +325,10 @@ unsigned DWARFVerifier::verifyUnitSection(const DWARFSection &S,
       case dwarf::DW_UT_split_type: {
         Unit = TypeUnitVector.addUnit(llvm::make_unique<DWARFTypeUnit>(
             DCtx, S, Header, DCtx.getDebugAbbrev(), &DObj.getRangeSection(),
-            DObj.getStringSection(), DObj.getStringOffsetSection(),
-            &DObj.getAppleObjCSection(), DObj.getLineSection(),
-            DCtx.isLittleEndian(), false, TypeUnitVector));
+            &DObj.getLocSection(), DObj.getStringSection(),
+            DObj.getStringOffsetSection(), &DObj.getAppleObjCSection(),
+            DObj.getLineSection(), DCtx.isLittleEndian(), false,
+            TypeUnitVector));
         break;
       }
       case dwarf::DW_UT_skeleton:
@@ -338,9 +339,10 @@ unsigned DWARFVerifier::verifyUnitSection(const DWARFSection &S,
       case 0: {
         Unit = CompileUnitVector.addUnit(llvm::make_unique<DWARFCompileUnit>(
             DCtx, S, Header, DCtx.getDebugAbbrev(), &DObj.getRangeSection(),
-            DObj.getStringSection(), DObj.getStringOffsetSection(),
-            &DObj.getAppleObjCSection(), DObj.getLineSection(),
-            DCtx.isLittleEndian(), false, CompileUnitVector));
+            &DObj.getLocSection(), DObj.getStringSection(),
+            DObj.getStringOffsetSection(), &DObj.getAppleObjCSection(),
+            DObj.getLineSection(), DCtx.isLittleEndian(), false,
+            CompileUnitVector));
         break;
       }
       default: { llvm_unreachable("Invalid UnitType."); }